Sorry if this has been asked before, but do I need to MFA my 5.6 lenses? I have Canon EF 400mm 5.6, EF-S18-55 mm 3.5/5.6 and EF-S 17-85 mm 4/5.6. These two zooms are only used at f5.6. I also have the EF 70-200 f4 IS. Cameras are a 7D2 and a 6D. I ask because a friend said only lenses less that f4 need to be microfocussed because the other lenses have more depth of field to cover focusing errors.